Commit 942cb357 authored Dec 22, 2020 by Casey Schaufler

Smack: Handle io_uring kernel thread privileges



Smack assumes that kernel threads are privileged for smackfs
operations. This was necessary because the credential of the
kernel thread was not related to a user operation. With io_uring
the credential does reflect a user's rights and can be used.

Suggested-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

parent 9b0072e2

security/smack/smack_access.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -688,9 +688,10 @@ bool smack_privileged_cred(int cap, const struct cred *cred)
		bool smack_privileged(int cap)
		{
		/*
		* All kernel tasks are privileged
		* Kernel threads may not have credentials we can use.
		* The io_uring kernel threads do have reliable credentials.
		*/
		if (unlikely(current->flags & PF_KTHREAD))
		if ((current->flags & (PF_KTHREAD \| PF_IO_WORKER)) == PF_KTHREAD)
		return true;

		return smack_privileged_cred(cap, current_cred());

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